Transcript Energy Balance and Body Composition

Chapter 9
Weight Management
Overweight
and
Underweight
Objectives of Chapter 9
• Identify how fat cells develop
• Identify causes of overweight and obesity
• Health risks associated with overweight
and obesity
• Aggressive treatments of obesity
• Weight loss strategies
Fat Cell Development
• Hyperplastic obesity
– Increase in number of fat cells
• Hypertrophic obesity
– Increase in size of fat cells
• Lipotoxicity
– Accumulation of fat in non adipose tissue. For
example, heart or liver increase risk of heart
failure and fatty liver
Fat Cell Development
Fat Cell Metabolism
• Lipoprotein lipase (LPL)
– Promotes fat stores
– Activity of LPL increase in obese people than
lean people
– LPL activity is different among male and female
– Fat breakdown is slower in women than men
– Release of fat in various body parts is different
for both sexes
– LPL activities increase after weight loss
contributing to more weight gain and “set point
theory”
Fat Cell Metabolism
• “Set point” (your internal thermostat)
– theory holds that body opposes weight loss
and works to maintain a set weight
– Provide an explanation that some inner
mechanism seems to set a person’s weight or
body composition at a fixed point.
– The body readjust after a weight loss to
restore that set point.
Prevalence of Obesity Among U.S.
Adults (BMI > 30)
• 1991: Only 4 states had obesity rates greater than
15%
• 1995: Over ½ of the states had obesity rates greater
than 15%
• 2000: Only 1 state had an obesity rate below 15%,
most had obesity rates greater than 20%, and one had
obesity rate greater than 25%
• 2005: All states have at least 15% obesity rate, only 4
states has obesity rate < 20%, 1/3rd of the states have
obesity rate > 25%, 3 states have rates > 30%
U.S. Obesity Trends 1985–2006
Adapted from: www.cdc.nccdphp/dnpa/obesity/trend/maps/index.htm
Overweight
• Overweight (BMI 25-29.9) and obesity (≥
30) are widespread health problems that
are continuing to increase.
• Many refer to overweight and obesity as
an epidemic.
• For good health, weight management is
important.
Body Weight, Body
Composition, and Health
• Health Risks of Overweight
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Diabetes
Hypertension
Cardiovascular disease Sleep apnea
Osteoarthritis (bone disease)
Some cancers
Gallbladder disease
Kidney disease
Respiratory problems
Complications in pregnancy and surgery
What Factors Are Likely to
Affect Body Weight?
What and how often you eat,
• Hunger and appetite affect what you eat.
– Appetite is psychological desire for food
– Hunger is physiological need for food,
subsides as feeling of satiation sets in
• Satiety determines length of time between eating
episodes
• environment
What Factors Are Likely to Affect
Body Weight?
Physiological feedback mechanisms
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involving mouth, stomach, intestines, and brain increase or
decrease hunger
– Many hormones play role:
• Ghrelin:
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produced in stomach
increases hunger and appetite
positive energy balance
High in obese people as well as people with eating disorder
Leptin:
– in fat tissue signals brain to decrease hunger and food intake.
– Promote negative energy balance
– May be deficient or defective in obese individuals, but very rare
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Cholecystokinin: released when stomach is distended,
increasing feelings of satiation, decreasing hunger
What Factors Are Likely to
Affect Body Weight?
• Genetics play a role in determining body weight
– Risk of becoming obese doubles if parents are
overweight, triples if obese, five times greater if
severely obese
• Genetic differences in level or function of
hormones, such as high ghrelin or low leptin
levels, increase obesity.
– Many obese have adequate leptin but brain has
developed resistance to it
What Factors Are Likely to
Affect Body Weight?
Environmental factors can increase appetite and
decrease physical activity.
• cheap and easily obtainable energy-dense foods
stimulate appetite
• We work more and cook less.
• About 1/3 calories come from ready-to-eat foods
prepared outside of home
• Frequent dining out associated with higher BMI
• Inadequate physical activities
• Americans eating about 300 calories/day more
than in 1985
What Is a Reasonable Rate of
Weight Loss?
• National Institutes of Health: overweight
individuals should aim to lose about 10%
of body weight over 6-month period
– Example: 180-lb person should lose 18
pounds/6 months = 3 lbs/month, ¾ lb/week
– To lose 1 lb of body fat, need 3,500 calorie
deficit
• Weight loss of ½-1 lb/week, need to decrease daily
calories by 250-500 calories
• Diet Meals video Overweight Children approach
to weight loss
Three Pieces of the Long-Term
Weight Loss Puzzle
How Can You Lose Weight
Healthfully?
Successful long-term weight loss requires
changes in three areas: diet, physical
activity, and behavior
– Eat smart, because calories count: add satiation
to low- calorie meals by including higher-volume
foods
• Eat more vegetables, fruit, and fiber
• Include some protein and fat in your meals
– Protein increases satiety most
– Fat slows movement of food from stomach into intestines
» Choose lean meat, skinless chicken, fish, nuts, and
unsaturated oils.
The Energy Density of Foods
Add high-volume fruits and
vegetables to displace higher
calorie foods.
The Volume of Food You Eat
How Can You Lose Weight
Healthfully?
Use MyPyramid as a weight-loss guide:
– High volume of fruits, vegetables, whole
grains, some lean protein, modest amounts of
fat
– Diet should contain variety of foods from all
food groups
• Replace higher-calorie foods with lower-calorie
options from each food group.
– Example: replace full-fat dairy with nonfat products
– Replace sodas with water
How Can You Lose Weight
Healthfully?
Move to lose
– 60 minutes/day of moderate-intensity activities can prevent
becoming overweight and aid in weight loss
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10,000 steps/day can reduce risk of becoming overweight
– Spot Reducing
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Regular aerobic exercise and weight loss will help trouble spots.
Strength training can improve muscle tone.
Stretching can help flexibility
– Exercise may help to curb appetite.
– Activity can reduce stress and improve self-esteem
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Break bad habits
– Behavior modification: change behaviors that contribute to
weight gain or impede weight loss
Fad Diets Are the Latest Fad
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Research shows that reduction of calories, not the
composition of the diet, is effective in weight loss.
People who adhere the longest to weight-loss diets lose
the most weight.
– High drop-out rates for most extreme diets (Atkins and
Ornish diets)
Beware of fad diet sensational claims and hype:
– “It’s the carbs, not calories, that make you fat!”
– Celebrity-endorsed miracle weight-loss products
– “Natural” substances help lose weight without risk
• How to get fat without really trying
What’s in the Fad Diets?
How Can You Maintain Weight
Loss?
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Weight cycling is a common result of fad diets.
Weight loss can be maintained if keep healthy habits
used during weight loss
New, lower weight requires less calories to maintain
weight
– Physical activity can close the “energy gap”, easier
than further reducing caloric intake
– 60-90 minutes/day of moderate-intensity physical
activity recommended to maintain weight loss
Aggressive Treatments of Obesity
• bariatric surgery – Gastric bypass and gastric
banding
– Results in dramatic weight loss and reduction of
hypertension, diabetes, high blood cholesterol,
and sleep apnea
– Risks include ulcers, gallstone, bleeding in
stomach and intestines
– for individuals with clinically severe obesity and
major medical problems.
– Changing and improving eating and exercise
habits offer the greatest benefit.
Aggressive Treatments of Obesity
bariatric surgery
– Over 100,000 is performed annually and numbers
continue to grow
– Limit food intake by reducing the capacity of the
stomach
– To qualify, a person must be at least 100lbs over their
ideal body weight or BMI > 40
– Must comply with prescribed diet
– At risk of iron, b12, folate, calcium and vit D
deficiencies
– Infections, nausea, vomiting, and dehydration is a
very real possibility after surgery
– Lifelong medical supervision is necessary
Gastric bypass surgery video
Aggressive Treatments of Obesity
• Drugs
– Sibutramine (meridia) suppresses the appetite and is
most effective when used with a reduced kcalorie diet
and increased physical activity. There are many side
effects.
– Orlistat (Xenical) blocks fat digestion and absorption.
There are many side effects. You can now get a low
dose over the counter under the brand name, Alli.
– Other drugs are still under study
• Liposuction is a popular procedure that is
primarily cosmetic but poses risk. Provides no
health benefit
How Much Should you Weigh?
Ideal Body Weight (IBW)
• Men
– 106 pound for the first 5 feet, + 6 pounds for
every inch over 5 feet. For example, a man
who is 6’1” have IBW of 184 pounds
• Women
– 100 pound for the fist 5 feet, + 5 pounds for
every inch over 5 feet. For example, a
woman who is 4’11” have IBW of 95 pounds
Extra Credit
• 10 points
– Use worksheet for chapter 9 to evaluate a
poplar weight loss program
– Must be typed
– No more than 1 page
– One word answer will not be accepted